ORCHARD HEATING 39 



Using the following figures for the constants : 



s $0.90 k=$0.14 Dh=$22 



r=$0.09 2 men at $2.50=$5 for L a night, and consider- 

 ing 1 100 heaters burning a gallon of oil during the night gives 

 Ab ( .90 .14) 22 



lOOx .09+5 lOOx .09+5 



n= .054 b 1.57 (7) 



This result is shown graphically in curve No. 1 of Figure 2, 

 the amount of fruit saved by. heating increasing as the number of 

 nights of heating increases, and where the number is large the 

 one nearly varies directly as the other; e. g., where b=300, we 

 get n=300x.054 1.57 or n=16.2 1.57, the latter term being 

 less than one-tenth of the former. 



Curve No. 1 shows graphically the relation between the 

 amount of fruit saved by heating 1 , and the number of times heat- 

 ing is resorted to during the year and is the plot df equation No. 

 7 considering the cost of oil as constant and as $.09 the figure 

 quoted by, the Standard Oil Company, f. o. b. Logan, and con- 

 sidering the selling price of the fruit as constant and as $.90 a 

 box. It shows that as the number of nights that the frost occurs 

 increases, the amount of fruit obtained by the farmer in excess 

 of that obtained by the man who doesn't heat, i. e., the amount 

 saved must increase. Unless he can actually heat a less number 

 of times than this and save this amount of fruit he will not be 

 financially ahead o!f the man who doesn't heat, This relation, 

 although established on the basis of money relations, represents 

 about what happens climatically because each frost in the spring 

 of the same degree kills approximately the same per cent of the 

 buds and the more nights of frost the less the yield of fruit in 

 the fall and the more nights that heating has to be resorted to. 

 If, therefore, considerable frost is experienced so that Dh is 

 small in comparison to the other factors, the question as to 

 whether one should heat his orchard or not is not a If unction of 

 whether there is much or little frost. In other words, a man in 

 one locality mfeht have to heat five nights to save his crop while 

 the other man in the same locality lost 25 per cent because of 

 not heating, and in another locality a farmer heated ten nights 

 at twice the cost and saved 50 per cent of the crop while the one 

 here who didn't heat lost 50 per cent and yet the value of the 

 50 per cent saved might be the same as the cost of the ten nights 

 of heating and the value of 25 per cent of the crop might be 



